The invention relates to improvements in rotary valve assemblies of the type shown in my U.S. Pat. No. 2,988,319 dated June 13, 1961, and U.S. Pat. No. 4,073,468 dated Feb. 4, 1978. In both of my aforesaid patents, a tapered rotary valve plug is disclosed for controlling a fluid flow path through a valve casing. To facilitate easier rotary operation of the valve plug, cam means is provided in each of my prior patents which reacts between the valve casing and the valve plug for lifting the valve plug from its seat.
In accordance with my U.S. Pat. No. 2,988,319, the cam means operates automatically to lift the valve plug from its seat during rotation of the valve plug to and from the closed and open positions.
In accordance with my U.S. Pat. No. 4,073,468, the cam means is incorporated into the valve plug actuating assembly so that rotation of the valve plug is delayed until the plug is lifted from its seat by the cam means. This is done by providing the valve plug with a separate operating head operatively coupled to the plug through a pin-and-slot connection and the provision of a spring means whereby rotation of the plug is delayed until the plug has been lifted from its seat, after which rotation of the plug is effected by the spring means.
Although both devices of the aforesaid patents have proved very successful for their purpose, the present invention improves on the details of construction in a number of ways to provide an even more effective valve assembly wherein a rotary tapered valve plug is axially displaced from its seat, rotated to the desired valving position in a floating condition and then forced tightly into sealing engagement with its seat.
The present invention eliminates the spring means as used in U.S. Pat. No. 4,073,468 which is relied on to delay rotation of the valve plug until the valve plug is lifted off its seat. This is done in the present invention by providing a novel handle assembly with a manually actuated coupling or locking pin by which the operating head and rotary valve plug are selectively coupled or uncoupled.
Also a positive sealing of the valve plug and seat is obtained in the present invention in both the open and closed positions. This is done by providing a camming action that forces the valve plug tight against the seat in both the open and closed positions by enabling the operating head to be rotated an additional increment beyond either the open or closed position of the valve plug and independently of the valve plug which is arrested against such additional rotary movement.
The above operations are made possible by reversing the taper of the valve plug and seat relative to the taper in my aforementioned patents and providing a novel handle assembly for cooperating with the operating head that has formed therein a pair of camming slots of improved design interacting with cam pins fixed to the valve casing.
The invention will be more readily understood by reference to the accompanying drawings and the following detailed description and claims.